Reciprocating apparatus

ABSTRACT

The apparatus comprises a carriage 3 moved to and fro alternately along a traverse 1 and which has two opposed resilient gudgeon pins 19 and 22. Each end of the traverse 1 carried a jack 33, 331 with the rods 37, 371 of which project inwardly. The carriage carries spindles 27, 271 resiliently mounted and each of which operates extensions 42, 421 of a slide valve of a distributor 34, 341 controlling the operation of the jacks 33, 331. When the spindle 27 comes against the extension 42 the distributor 34 is operated and causes the advance of the piston rod 37 which drives the carriage 3 back. When the latter arrives at the other end of the traverse the jack 331 reverses the drive. The apparatus is particularly applicable for paint spraying on surfaces.

United States Patent [191 Guillaud 1 RECIPROCATING APPARATUS [75]inventor: Michel Guillaud, Grenoble, France [73] Assignee: Secmer, S.A.,lsere, France [22] Filed: June 18, 1973 [211 App]. No.: 370,639

1 June 17, 1975 3,796,184 3/1973 Howkins 118/323 Primary ExaminerPaul E.Maslousky Attorney, Agent, or Firm--Dowe1l and Dowell 5 7 ABSTRACT Theapparatus comprises a carriage 3 moved to and fro alternately along atraverse 1 and which has two opposed resilient gudgeon pins 19 and 22.Each end of the traverse 1 carried a jack 33, 33' with the rods 37, 37of which project inwardly, The carriage carries spindles 27, 27resiliently mounted and each of which operates extensions 42, 42 of aslide valve of a distributor 34, 34 controlling the operation of thejacks 33, 33 When the spindle 27 comes against the extension 42 thedistributor 34 is operated and causes the advance of the piston rod 37which drives the carriage 3 back. When the latter arrives at the otherend of the traverse the jack 33' reverses the drive. The apparatus isparticularly applicable for paint spraying on surfaces.

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RECIPROCATING APPARATUS The present invention relates to improvements inreciprocating apparatus. that is to say. intended to permit the to andfro displacement of a member along a slide this displacement beingeffected generally in a transverse manner with regard to the geometricalaxis of a machine.

The known devices of the kind in question are generally realized bymeans of a shaft grooved by at least two contrary helicoidal peripheralgrooves and on which is engaged a nut connected to the member which itis desired to displace to and fro along the bar. This latter is actuatedby a unidirectional movement of rotation and the nut carries a catchwhich cooperates with one of the helicoidal grooves of the shaft so thatthis nut is given a to and fro linear movement. At the end of the barthe catch changes the groove automatically so that its movement isreversed after each traverse.

It can be easily seen that reciprocating apparatus can be obtained byutilising other well known mechanical elements such as chains, belts andthe like.

The known reciprocating devices have drawbacks resulting from theircomplexity or from their high cost price. In any case they compriseelectrical contacts which only permit with difficulty their use in anexplosive atmosphere.

The improvements which form the subject of the present invention aim atremedying the above mentioned drawbacks and permitting the realizationof an anti-deflagrating sliding device which is of simple and economicrealization.

The reciprocating device according to the invention of the kindcomprising a tool carrying carriage reciprocating to and fro along aslide. characterised in that the aforementioned slide is provided withtwo percussion mechanisms disposed one at each of its ends and which actin turn on one of two gudgeon pins resiliently and slidably on mountedwith the carriage to reverse the direction of travel of the carriage atthe extreme position selected for the end of its run in each direction.

According to one preferred embodiment each percussion mechanism isconstituted by a compressed air jack controlled by a distributor thecontrol lever of which is operated by a boss resiliently mounted on thecarriage. The gudgeon pins of the carriage are preferably disposedco-axially and they are each thrust in the direction of thecorresponding jack by means of a single compression spring placedbetween the gudgeon pins.

The invention will be described with reference to the accompanyingdrawings by way of example, to permit better understanding of theinvention, the features which it has and the advantage which it iscapable of providing:

FIG. 1 is a side elevation of an apparatus according to the invention;

FIG. 2 is an enlarged cross section on line II-II (FIG.

FIGS. 3 and 4 are detail elevations to a larger scale showing theoperation of the reversing of the direction of the carriage of theapparatus;

FIG. 5 shows diagrammatically to a smaller scale the curve traced by astylus carried by a carriage on a band running at constant speed atright angles to the direction of movement of the stylus.

There is shown in FIG. I an apparatus according to the inventioncooperating with a traverse 1 associated with two vertical uprightsresting on the ground on their lower ends 20. The traverse 1 may beplaced at any height whatever along the uprights 2 with the aid ofmeans. not shown.

The aforementioned apparatus comprises a carriage 3 travelling to andfro alternately along the traverse l and two direction reversingmechanisms 4, 4'.

The traverse l is made in the form of a U-shaped girder (FIG. 2) the webof which is disposed vertically. Each of the flanges of this traversecarries a rail 5, 5 having in cross-section the form of a rectangle thelower face of which is grooved by a V groove 6, 6'. The two rails 5 and5' are situated in two vertical planes offset in respect of one anotherthe upper rail 5 being fixed nearer the traverse 1 than the lower rail5.

The carriage 3 has a general cylindrical shape and it is provided withtwo arms 7, 7' extending parallel to the rails 5 and 5' with bearings 8carried by the arms 7, 7' the balls of which engage the grooves 6 and 6'in the rails 5, 5'. The carriage 3 may comprise any tool carrier but inthe present example it carries a gun 9 (FIG. 1) projecting therefrom andcapable of directing paint or any other product onto a support 10 whichpasses at right angles to the direction of travel of the traverse lresting on a base 11.

The body 12 of the carriage 2 has an axial bore 13 the geometrical axisof which is arranged parallel to that of the rails 5, 5'. This bore 13is stepped at each end of the body 12 to constitute two end bores 14 ofgreater diameter. The bores I3 and 14 thus define two shoulders 15against each of which is supported an annular washer 16 made ofanti-deflecting material and resistant to compression. Each of thesewashers is held in place by means of a split pin or circlip l8 engagingin a groove 14a of each bore 14. A gudgeon pin 19 engages in the groovesofa stuffing box I7 and the washer 16 extending to one of the ends ofthe body 12. The inner part of this gudgeon pin is provided with aperipheral collar 20 and an axial shank 21.

Another gudgeon pin 22 engages in the bores of the stuffing box 17 andthe washer 16 located at the end of the body 12 opposite to that whichreceives the gudgeon pin 19. The gudgeon pin 22 is provided with aperipheral collar 23 arranged inside the bore 13 and integral with asleeve 24 incorporating an annular ring 25 into which enters the shank21 of the gudgeon pin 19. Between the collars 20 and 23 and co-axialwith the two gudgeon pins 19 and 23 there is mounted a compressionspring 26.

The construction is such that the gudgeon pins 19 and 22 project to anequal length from each end of the body 12 of the carriage 3.

The carriage 3 is provided with two cylinders 27 and 27' having the samegeometrical axis arranged parallel to that of the bore 13. These twoblind cylinders 27 and 27' are open in the same direction respectivelyas the gudgeon pins 19 and 22, that is to say, in opposite directions.On the inside of each cylinder 27, 27' is mounted a piston 28, 28'integral with a spindle 29, 29' the free end of which is terminated by aboss 30, 30'. Each spindle 29, 29' passes through the open end of thecorresponding cylinder through the bore of an appropriate stuffing box31, 31'. A compression spring 32, 32' is mounted in each cylinder 27,27' the ends of which are supported against, on the one hand the ends ofthese cylinders and on the other hand the corresponding piston 28, 28'.

Each ofthe mechanisms 4, 4 is constituted by a jack 33, 33' connected toa distributor 34, 34' (FIG. 1).

The jack 33 (FIGS. 3 and 4) comprises a cylinder 35 in which is axiallymounted a piston 36 the rod 37 of which passes out of this cylinder andin the direction of the carriage 3. This jack 33 is of the double actiontype. that is to say. the compressed air is sent alternately to thefront of the piston 36 through the piping 38 to cause this latter torecede and to the rear of this piston by means of the piping 39 to causeit to advance. The distributor 34 to which are connected the pipings 38and 39 directs the compressed air coming from a piping 40 towards one orother of the aforementioned pipings by means ofa slide valve 41 whichhas an extension 42 directed in line with the spindle 29 of the carriage3.

The carriage 3 has a boss 43 (FIG. 1) with its axis parallel to that ofthe bore 13 of the body 12 and the blind bore of which, not shown. isopen in the direction to the right in the FIG. 1. This bore is connectedto a source of compressed air by means of a stop valve.

The operation is as follows:

The carriage 3 being in any position between the two mechanisms 4, 4,the valve which controls the arrival of compressed air into the bore ofthe bore 43 is opened. The air escaping through the opening of this boredisplaces the carriage 3 in the direction to the left according to theprinciple of equality of action and reaction.

When the carriage arrives in the proximity of the mechanism 4 the valveis closed again so that the carriage continues to run by inertia (FIG.3). At the precise moment when the boss 30 comes into contact with theend of the extension 42 of the valve 41 the end of the gudgeon pin 19 isat such a distance from the free end of the piston rod 37 of the jack 33that when the slide valve 4] has travelled its whole run, the gudgeonpin 19 and the piston rod 37 are practically in contact. At this momentthe compressed air arrives through the piping 39 and the piston 36 ofthe jack 33 is strongly actuated in the direction to the right (FIG. 4).This impulse is absorbed partly by the spring 26 the residual forceserving to give the carriage 3 a movement from left to right. The pistonrod 37' of the jack 33' of the mechanism 4 is at this moment retracteddue to the fact that air is driven through the piping 38 by movement ofthe piston 36 to the right in the jack 33 and is directed into the jack33 so as to cause its piston 36' to retract. When the carriage 3 arrivesadjacent to the mechanism 4' the same movements are produced as thosedescribed with reference to FIGS. 3 to 4 so that the direction ofmovement of the carriage is reversed.

A reciprocating device is thus realized the speed of displacement ofwhich is constant over the whole length of its course as follows fromthe diagram of FIG. 5. In fact each advance and each return of a styluscarried by the carriage 3 and resting on a sheet of paper which passesat constant speed in the direction of the arrow F is a straight line.

It is obvious that the course of the carriage 3 which is particularlyprecise may be easily regulated by displacing the mechanisms 4, 4' alongthe traverse l by means, not shown, and the speed of the carriage may bevaried by varying the compressed air pressure. Of course thecharacteristics of the spring 26 are only valid for a certain range ofvariation of speeds; if the speed increases or decreased beyond thelimit of this range the characteristics of this spring must be changed.The speed may moreover be raised to high levels. that is to say, it mayreach a value of about three metres per second without any shock beingobservable at the moment of reversal of the direction of displacement.

One could furthermore if it were necessary reduce the speed of thecarriage at the end of the run by fixing the jacks 33, 33' by means ofrubber blocks.

It will be noted finally that the springs 32 prevent any deteriorationof the distributor 34 or of the spindle 29 in case of any malfunction ofthe normal working of the change of direction. for example, at the timeofa severe lack of compressed air.

It must furthermore be understood that the preceding description hasbeen given only by way of example and that it in no way limits the scopeof the invention.

What I claim is:

1. Apparatus for reciprocating a carriage which is mounted to movefreely to and fro between two extreme positions upon a traverse girder.said apparatus comprising:

a. a source of fluid under pressure;

b. on the girder at each of said extreme positions a fluid impulsemechanism operative to deliver thrust to said carriage when it reachesthe extreme position to cause it to travel by inertia to the oppositeextreme position; and valve means coupled between said source and eachimpulse mechanism and operative when actuated to deliver fluid pressureto the impulse mechanism;

c. on said carriage arm means located to actuate the valve means whenthe carriage reaches each of said extreme positions thereby topressurize the adjacent impulse mechanism, and said carriage com prisinga body having a bore extending therethrough and aligned with said fluidimpulse mechanism, a pair of axially aligned gudgeon pins extending fromboth sides of the body and reciprocably captivated in the bore anddisposed respectively to receive the thrust from one of said impulsemechanisms, and spring means in the bore urging the pins outwardlythereof, whereby the pins cushion the impact of the impulse mechanisms.

2. Apparatus as set forth in claim I, wherein each of said impulsemechanisms comprises a jack having a piston member extended in thedirection of the carriage when the jack is pressurized.

3. Apparatus as set forth in claim 2, wherein each jack comprises adouble acting fluid pressure piston, each valve means being connected toenter fluid pressure into a space behind the piston of the correspondingjack to advance it toward the carriage, and the jacks having fluidspaces in front of their pistons which spaces are mutually connectedtogether so that one piston is retracted when the other is advanced.

4. Apparatus as set forth in claim 1, wherein said arm means on thecarriage comprise oppositely facing spindles located to abut a valvemeans when the carriage reaches an extreme position and thereby actuateit to pressurize the corresponding impulse mechanism.

5. Apparatus as set forth in claim 4, wherein each of said spindles isreciprocably mounted in a bore in the carriage and spring loaded to urgeit in the direction of the valve means which it must actuate.

6. Apparatus as set forth in claim 1, including a compressed air nozzleon the carriage and facing in one direction of travel thereof andpressurizable to displace the carriage toward the opposite impulsemechanism to initially start the movement thereof.

1. Apparatus for reciprocating a carriage which is mounted to movefreely to and fro between two extreme positions upon a traverse girder,said apparatus comprising: a. a source of fluid under pressure; b. onthe girder at each of said extreme positions a fluid impulse mechanismoperative to deliver thrust to said carriage when it reaches the extremeposition to cause it to travel by inertia to the opposite extremeposition; and valve means coupled between said source and each impulsemechanism and operative when actuated to deliver fluid pressure to theimpulse mechanism; c. on said carriage arm means located to actuate thevalve means when the carriage reaches each of said extreme positionsthereby to pressurize the adjacent impulse mechanism, and said carriagecomprising a body having a bore extending therethrough and aligned withsaid fluid impulse mechanism, a pair of axially aligned gudgeon pinsextending from both sides of the body and reciprocably captivated in thebore and disposed respectively to receive the thrust from one of saidimpulse mechanisms, and spring means in the bore urging the pinsoutwardly thereof, whereby the pins cushion the impact of the impulsemechanisms.
 2. Apparatus as set forth in claim 1, wherein each of saidimpulse mechanisms comprises a jack having a piston member extended inthe direction of the carriage when the jack is pressurized.
 3. Apparatusas set forth in claim 2, wherein each jack comprises a double actingfluid pressure piston, each valve means being connected to enter fluidpressure into a space behind the piston of the corresponding jack toadvance it toward the carriage, and the jacks having fluid spaces infront of their pistons which spaces are mutually connected together sothat one piston is retracted when the other is advanced.
 4. Apparatus asset forth in claim 1, wherein said arm means on the carriage compriseoppositely facing spindles located to abut a valve means when thecarriage reaches an extreme position and thereby actuate it topressurize the corresponding impulse mechanism.
 5. Apparatus as setforth in claim 4, wherein each of said spindles is reciprocably mountedin a bore in the carriage and spring loaded to urge it in the directionof the valve means which it must actuate.
 6. Apparatus as set forth inclaim 1, including a compressed air nozzle on the carriage and facing inone direction of travel thereof and pressurizable to displace thecarriage toward the opposite impulse mechanism to initially start themovement thereof.